This application relates generally to gas turbine engines and, more particularly, to methods and apparatus for injecting fluids into turbine engines.
Air pollution concerns worldwide have led to stricter emissions standards both domestically and internationally. These same standards have caused turbine engine manufacturers to design more efficient engines, as well as design improved retrofit components that enable engines to operate more efficiently, with improved emissions, and/or with extended useful life and reliability. Moreover, the generally high capital costs associated with the purchase and maintenance of turbine engines, such as revenue losses generated during engine outages, have caused the same engine manufacturers to attempt to design engines that are more reliable and that have extended useful life.
Controlling the mixture of fluids, i.e. gas and steam, delivered to a gas turbine engine may be critical to the engine's performance and/or emissions. At least some known gas turbine engines operating with gas and steam do not meet emissions requirements at all operating conditions, and in particular, such engines generally do not satisfy carbon monoxide (CO) emission requirements as well as other known engines. For example, at least some known dual fuel gas turbine engines utilizing gas and steam generate higher CO emissions than dual fuel gas turbine engines utilizing gas and water. More specifically, poor mixing of the gas and steam may cause fuel to remain towards a centerline of the nozzle, leading to higher CO emissions being generated. Moreover, the axial, non-swirled injection of the gas and steam may cause the recirculation stability zone within the combustor to be shifted downstream, which may cause the flame to become detached, resulting in the generation of CO emissions.